The invention relates to a process for dry dispersal of particles, and an instrument for dry dispersal of particles for producing on specimen slides a random, homogeneous fine distribution (a dispersal) of dry, fine, grainy bulk materials whose particle size distributions can be analyzed, for example, by means of automatic image analysis.
It is known that particles whose particle size distribution is to be determined by optical means through automatic image analysis must be dispersed perfectly in order to avoid so-called agglomerates (clotting-together of individual particles). Such agglomerations give rise to assessment errors and incorrect measurements. Likewise, two particles touching by chance on the specimen slide likewise simulate a (single) particle which is too large. In order to avoid these errors, it was hitherto necessary to apply the particles in highly dilute form - i.e. with a relatively large separation between the individual particles - to the specimen slide. However, the number of particles covered per image field is then impermissibly small or the evaluation times are too long. Fine powders cannot be formed on the specimen slide without agglomeration using conventional methods. The object of the present invention is therefore to provide a process and an instrument with which it becomes possible to disperse, in optimum fashion, fine, dry, grainy bulk goods (powders, dusts) and to apply them in the densest possible form onto a specimen slide, without the particles touching one another, so that such substances become more accessible for particle size determination by means of automatic image analysis.